Semiconductor device and manufacturing method of the same

Abstract

Provided is a technique of effectively removing a metallic element that has catalytic action in terms of the crystallization of a semiconductor film and remains in a semiconductor film obtained using the metallic element. With the technique of the present invention, to remove a catalytic element used to crystallize a semiconductor film having an amorphous structure, gettering is completed by forming a region or a semiconductor film, to which a rare gas element is added, and by having the catalytic element move to the formed region or semiconductor film.

What is claimed is: 
     
       1. A method of manufacturing a semiconductor device comprising:
 forming a first semiconductor film comprising an amorphous silicon over a substrate having an insulating surface; 
 adding a material comprising a metal for promoting crystallization to the first semiconductor film; 
 performing a first heating process to the first semiconductor film, thereby forming the first semiconductor film having a crystal structure; 
 forming a barrier layer on a surface of the first semiconductor film having the crystal structure; 
 forming a second semiconductor film containing a rare gas element by using a mixed gas of the rare gas and hydrogen on the barrier layer, whereby the second semiconductor film has low density to enhance etching selectivity with the first semiconductor film having the crystal structure; 
 performing gettering through. a second heating process, thereby moving the metal for promoting crystallization to the second semiconductor film; 
 removing the second semiconductor film; and 
 irradiating the first semiconductor film having the crystal structure with laser light. 
 
     
     
       2. A method of manufacturing a semiconductor device according to  claim 1 , wherein the rare gas element is added simultaneously with the formation of the second semiconductor film. 
     
     
       3. A method of manufacturing a semiconductor device according to  claim 1 , wherein the rare gas element is added after the formation of the second semiconductor film. 
     
     
       4. A method of manufacturing a semiconductor device according to  claim 1 , wherein the barrier layer is formed from a chemical oxide film that is formed using ozone water. 
     
     
       5. A method of manufacturing a semiconductor device according to  claim 1 , wherein the barrier layer is formed by oxidizing a surface of the barrier layer through a plasma process. 
     
     
       6. A method of manufacturing a semiconductor device according to  claim 1 , wherein the barrier layer is formed by oxidizing a surface of the barrier layer by generating ozone through irradiation with ultraviolet rays in an oxygen containing atmosphere. 
     
     
       7. A method of manufacturing a semiconductor device according to  claim 1 , wherein the rare gas element is at least one selected from the group consisting of He, Ne, Ar, Kr, and Xe. 
     
     
       8. A method of manufacturing a semiconductor device according to  claim 1 , wherein the rare gas element is added using one of an ion implantation method and an ion doping method. 
     
     
       9. A method of manufacturing a semiconductor device according to  claim 1 , wherein the first heating process is performed by radiation from a light source, the light source comprising at least one selected from the group consisting of a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high pressure sodium lamp, and a high pressure mercury lamp. 
     
     
       10. A method of manufacturing a semiconductor device according to  claim 1 , wherein the first heating process is performed with a furnace annealing method that uses an electric heating furnace. 
     
     
       11. A method of manufacturing a semiconductor device according to  claim 1 , wherein the second heating process is performed by radiation from a light source, the light source comprising at least one selected from the group consisting of a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high pressure sodium lamp, and a high pressure mercury lamp. 
     
     
       12. A method of manufacturing a semiconductor device according to  claim 1 , wherein the second heating process is performed with a furnace annealing method that uses an electric heating furnace. 
     
     
       13. A method of manufacturing a semiconductor device according to  claim 1 , wherein the metal for promoting crystallization is at least one selected from the group consisting of Fe, Ni, Co, Ru, Rh, Pd, Os, Ir, Pt, Cu, and Au. 
     
     
       14. A method for manufacturing a semiconductor device according to  claim 1 , wherein the second semiconductor film is formed by a plasma CVD method and a high-frequency sputtering method. 
     
     
       15. A method for manufacturing a semiconductor device. according to  claim 1 , wherein the second semiconductor film contains 25 to 40 atom % hydrogen. 
     
     
       16. A method for manufacturing a semiconductor device according to  claim 1 , wherein the laser light is a second harmonic or a third harmonic of a solid-state laser. 
     
     
       17. A method of manufacturing a semiconductor device comprising:
 forming a first semiconductor film comprising an amorphous silicon over a substrate having an insulating surface; 
 adding a material comprising a metal for promoting crystallization to the first semiconductor film; 
 performing a first heating process to the first semiconductor film, thereby forming the first semiconductor film having a crystal structure; 
 forming a barrier layer on a surface of the first semiconductor film having the crystal structure; 
 forming a second semiconductor film containing a rare gas element by using a mixed gas of the rare gas and hydrogen on the barrier layer, whereby the second semiconductor film has low density to enhance etching selectivity with the first semiconductor film having the crystal structure; 
 performing gettering through a second heating process, thereby moving the metal for promoting crystallization to the second semiconductor film; 
 removing the second semiconductor film; 
 removing the barrier layer after removing the second semiconductor film; and 
 irradiating the first semiconductor film having the crystal structure with laser light. 
 
     
     
       18. A method of manufacturing a semiconductor device according to  claim 17 , wherein the rare gas element is added simultaneously with the formation of the second semiconductor film. 
     
     
       19. A method of manufacturing a semiconductor device according to  claim 17 , wherein the rare gas element is added after the formation of the second semiconductor film. 
     
     
       20. A method of manufacturing a semiconductor device according to  claim 17 , wherein the barrier layer is formed from a chemical oxide film that is formed using ozone water. 
     
     
       21. A method of manufacturing a semiconductor device according to  claim 17 , wherein the barrier layer is formed by oxidizing a surface of the barrier layer through a plasma process. 
     
     
       22. A method of manufacturing a semiconductor device according to  claim 17 , wherein the barrier layer is formed by oxidizing a surface of the barrier layer by generating ozone through irradiation with ultraviolet rays in an oxygen containing atmosphere. 
     
     
       23. A method of manufacturing a semiconductor device according to  claim 17 , wherein the rare gas element is at least one selected from the group consisting of He, Ne, Ar, Kr, and Xe. 
     
     
       24. A method of manufacturing a semiconductor device according to  claim 17 , wherein the rare gas element is added using one of an ion implantation method and an ion doping method. 
     
     
       25. A method of manufacturing a semiconductor device according to  claim 17 , wherein the first heating process is performed by radiation from a light source, the light source comprising at least one selected from the group consisting of a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high pressure sodium lamp, and a high pressure mercury lamp. 
     
     
       26. A method of manufacturing a semiconductor device according to  claim 17 , wherein the first heating process is performed with a furnace annealing method that uses an electric heating furnace. 
     
     
       27. A method of manufacturing a semiconductor device according to  claim 17 , wherein the second heating process is performed by radiation from a light source, the light source comprising at least one selected from the group consisting of a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high pressure sodium lamp, and a high pressure mercury lamp. 
     
     
       28. A method of manufacturing a semiconductor device according to  claim 17 , wherein the second heating process is performed with a furnace annealing method that uses an electric heating furnace. 
     
     
       29. A method of manufacturing a semiconductor device according to  claim 17 , wherein the metal for promoting crystallization is at least one selected from the group consisting of Fe, Ni, Co, Ru, Rh, Pd, Os, Ir, Pt, Cu, and Au. 
     
     
       30. A method for manufacturing a semiconductor device according to  claim 17 , wherein the second semiconductor film is formed by a plasma CVD method and a high-frequency sputtering method. 
     
     
       31. A method for manufacturing a semiconductor device according to  claim 17 , wherein the second semiconductor film contains 25 to 40 atom % hydrogen. 
     
     
       32. A method for manufacturing a semiconductor device according to  claim 17 , wherein the laser light is a second harmonic or a third harmonic of a solid-state laser.